Bottom Line:
Recurrences are common, and late metastases have been recorded.Because of the similarities, both lesions are considered to be a single entity within the spectrum of low-grade sarcomas.Two cases of HSCTGR occurring in the lower limb are described in this report.

Low-grade fibromyxoid sarcomas are uncommon deep-seated soft tissue neoplasms that exhibit a deceptively benign appearance microscopically. The finding of a linear or whorled array of spindled cells with few or no mitoses in a characteristic myxoid stroma can pose diagnostic dilemmas. Recurrences are common, and late metastases have been recorded. A closely related tumor, the so-called hyalinizing spindle cell tumor with giant collagen rosettes (HSCTGR), has also been described, with both the neoplasms having a similar cytogenetic abnormality and clinical behavior. Because of the similarities, both lesions are considered to be a single entity within the spectrum of low-grade sarcomas. Two cases of HSCTGR occurring in the lower limb are described in this report.

Mentions:
Microscopic examination in both cases revealed well-circumscribed tumors composed of spindle-shaped, bland-looking cells having a fascicular and a vaguely storiform pattern (Figure 2). The cellularity varied. Some areas showed spindle cells arranged in irregular crisscrossing fascicles separated by a moderate amount of collagen, often with a ‘cracking’ artifact around the elongated fibroblastic cells. In other areas there was extensive stromal hyalinization, with a paucity of neoplastic cells, and in yet others, the stroma was exceedingly myxoid (Figure 3), with widespread separation of the neoplastic cells. In the myxoid zones, the tumor was composed of bland spindled-to-stellate cells in a myxoid-to-lightly collagenized stromal background, often with associated curvilinear-to-branching prominent vasculature (Figure 4). At places the spindle cells had a wavy irregular outline. There was no mitotic activity detectable.

Mentions:
Microscopic examination in both cases revealed well-circumscribed tumors composed of spindle-shaped, bland-looking cells having a fascicular and a vaguely storiform pattern (Figure 2). The cellularity varied. Some areas showed spindle cells arranged in irregular crisscrossing fascicles separated by a moderate amount of collagen, often with a ‘cracking’ artifact around the elongated fibroblastic cells. In other areas there was extensive stromal hyalinization, with a paucity of neoplastic cells, and in yet others, the stroma was exceedingly myxoid (Figure 3), with widespread separation of the neoplastic cells. In the myxoid zones, the tumor was composed of bland spindled-to-stellate cells in a myxoid-to-lightly collagenized stromal background, often with associated curvilinear-to-branching prominent vasculature (Figure 4). At places the spindle cells had a wavy irregular outline. There was no mitotic activity detectable.

Bottom Line:
Recurrences are common, and late metastases have been recorded.Because of the similarities, both lesions are considered to be a single entity within the spectrum of low-grade sarcomas.Two cases of HSCTGR occurring in the lower limb are described in this report.

Low-grade fibromyxoid sarcomas are uncommon deep-seated soft tissue neoplasms that exhibit a deceptively benign appearance microscopically. The finding of a linear or whorled array of spindled cells with few or no mitoses in a characteristic myxoid stroma can pose diagnostic dilemmas. Recurrences are common, and late metastases have been recorded. A closely related tumor, the so-called hyalinizing spindle cell tumor with giant collagen rosettes (HSCTGR), has also been described, with both the neoplasms having a similar cytogenetic abnormality and clinical behavior. Because of the similarities, both lesions are considered to be a single entity within the spectrum of low-grade sarcomas. Two cases of HSCTGR occurring in the lower limb are described in this report.